My manipulate axis is skewed
Consider pressing the different keys on your numeric keypad.
This will align your view to an axis in the set {XYZ}.

NumberPad 1
NumberPad 3
NumberPad 7 with/without the variation of 
Ctrl

https://docs.blender.org/manual/en/dev/editors/3dview/navigate/align.html



Consider changing the 

transformation orientation to 

[Global]

as indicated by the yellow arrow.

Sometimes a rogue keystroke or click can change a setting unbeknownst to many.

If your 3D mesh above is not time consuming ... I would just consider archiving mesh file. Similar to a delete. Create a new file and start over.  You probably wont make the same mistake.  Starting over may be more cost effective than chasing down one little small problem and trying to remember your actions or describe it.